Alternating current mercury vapor apparatus



Oct. 18, 1932.

F. REYNOLDS ET AL ALTERNATING CURRENT MERCURY VAPOR APPARATUS Filed Jan. 12, 1928 Patented Get. 18, 1932 unrreo STATES.

purer FREDERICK nnYNoLDs AND ARTHUR LEONARD Lens, or WALKERVILLE, nnwons'rnn uron rynn, ENGLAND, ASSIGNORS, TO THE THERMAL SYNDICATE LTI F WALLSEND-UPON-TYNE, ENGLAND, A'CORPORATION OF ENGLAND ALTERNATINGCURRENT MERCURY VAPOR APPAIBIATUS- Application filed January 12, 1928, Serial No.

This invention relates to alternating current mercury vapor apparatus of the vacuum type comprising an arc tube preferably of quartz, having at one end of the apparatus a cathode and at the other end a pair of anodes.

It is well knownthat for the successful operation of such apparatus, the main difiiculty to be overcome is that ofreadily starting the arc. In starting, the usual method is to tilt the apparatus until a-stream-oi' mercury runs up the arc tube from each anode and connects with the cathode so as to complete the arc tube circuit, and then to bringthe apparatus back to its normal position, the apparatus being constructed so that the stream of mercury from each anode is interrupted as simultaneously as possible atthe point where the two streams join the cathode. This operation is not, however, successful unless means are provided. for avoiding short circuiting of the two anodes.

It is well known that in such apparatus, as at present constructed, that is to say, in which the cathode is at one end of the arc tube, the two anodes being at the other end of the said tube, this diiiiculty can be overcome by providing a web or ridge of quarts on the bottom of the arc tube for the purpose of separating the mercury in the two anodes.

We have now found that the difficulty 're ferred to can also be overcome forming a small channel or gutter, in the bottom of the tube, starting at the mouth of the capillary portion of th cathode, or if no capillary portion is used, starting at the end of the cathode itself, and extending to thepart where the mercury returning to the anodes will divide. The are tube of the apparatus is preferably made V shaped with the limbs of the V close together, the anodesbcing situated at the ends of the said tube and the cathode at the joint of the V. The channel in this case extends across the joint of the V and may .be formed in the quartz after the apparatushas been shaped, and is produced by blowing and/or pressing the quartz at the desired place, after first softening thequartz in a blowpipe.

.Y The principal object of the present invention is to provide an improved mercury vapor tubes otfthis character.

246,123, and in Great Britain March 18, 1927.

OFFICE;

arc tube in which the streams of mercury.

connected to each anode and the cathode are broken practically simultaneously so as to strike anarc when the tube is moved back to c the operating position after having been tilted to cause the mercury streams to flow together to complete the arc tube circuit.

A further object of the invention is to cheapen and improve the. construction of In order that the invention may be fully understood one manner of carrying it out in practice will be described withreference to the accompanying drawing in whichFigures 1 and 2 are an elevation and plan respeclively of an apparatus 1n accordance with theinvention. r

The apparatus, which is preferably made of quartz, comprises a V shaped tube having limbs 1 and 2 each limb being provided at its end with an anode 3 and 4. A short tube 5 connects the joint of the V with the cathode 6. The anodes and the cathode are in communication through tubes 7, 8 and 9 with the electrodes 10, 11 and 12.. The tube 5 which is herein referred to as the capillary portion of the cathode, is provided at its upper portion with a channel or gutter 13 which extends across the joint of the Vof the arc tube.

In operation the apparatus is tilted in usual way and lowered to allow the mercury I to return to the anodes. During the lowering,

a portion of the mercury remains in the channel or gutter 13 in the form of a small stream which connects with the mercury ,in the cathode vessel 6. The mercury flowing;

back to the two anodes by way of the divided arc tube 1 and 2 takes the form of two streams which are approximately equal in volume and which are moving at the same rate. These two streams break away from the mercury. J

the mercury in the channel orgutter 13 which is connected with thecathode-vessel 6.I No short circuit between the anodes 3'and can take place because the mercury ,from" these anodes is flowing in the divided portion of the arc tube. Owing to the very small volume of mercury in the channel or gutter 13, this quickly vaporizes the arc travelling back along the channel until it reaches its final position inthe capillary portion of the cathode vessel.

B making the apparatus of form accor ing to the preferred construction so that the axes of the anode vessels are at only a small angle to the centre line of the apparatus when viewed in plan, and not at right angles as is usual, this has the advantages of cheapening the construction and reducing the overall-width of the apparatus while the mercury can be so positioned as readily to flow into the arc tubes when the apparatus i is tilted for starting. These two latter advantages can even further be increased if desired, if the anode vessels are placed with their axes parallel to each other so that the anode vessels are as close tog-ether as is practicable. In fact, the limbs 1 and 2 can them selves be made parallel for example U shaped; this is not, however, shewn in the drawing.

Having now particularly described and ascertained the nature of our said invention and in What manner the same is to be performed, we declare that what we claim is 1. An alternating current mercury vapor apparatus as defined in claim 6 in which the tube portions within which the anodes are located are positioned relatively close together.

2. An alternating current mercury vapor apparatus as defined in claim 6 in which the channel is of small capacity so that it will contain a relatively small amount of mercury when the tube is returned to the operating position after it has been tipped to start the operation.

3. Alternating current mercury vapor apparatus comprising an arc tube and a pair of anode tubes communicating therewith and forming acute angles with each other and joining said are tube at substantially a common point so that mercury flowing therethrough will divide into substantiallyequal streams for the several anode tubes, and a depression in the bottom of the arc tube along a line between the two anode tubes so tha the streams of mercury flowing into the several anode tubes will separate from each other and from the mercury remaining in the de pression substantially simultaneously.

4. Alternating current mercury vapor apparatus comprising an arc tube having a cathode chamber atone end thereof, and a plurality of anode tubes diverging from the groove being adapted to hold a thread of mercury in electrical contact with the cathode which will be almost instantly vaporized by the heat of the are when struck.

5. Alternating current mercury vapor apparatus comprising an arc tube having a cathode chamberand a plurality of the anode chambers located therein, the bottom of said tube being V-shaped in plan and substan tially the same level in the two arms of the J so as 0 divide equally to the two anodes a stream of mercury flowing from the cathode and having a narrow depressed channel between the cathode and the inner vertex of said l with its bottom inclined downwardly from the vertex of the V toward the cathode, where by the cathode will be connected by a narrow thread of mercury to streams of mercury in both arms of the V at the instant that they break apart.

6. Alternating current mercury vapor apparatus comprising an arc tube having a cathode and a pair of anodes located therein, said are tube being divided so as to divide between the anodes a stream of mercury flowing toward the anode end of the tube, and having a narrow channel extending toward the cathode from the point in the tube where the mercury divides when it flows back to the anodes. v

7. Alternating current mercury vapor apparatus comprising an arc tube having a cathode located therein and formed with joined tube portions within each of which an anode is located and a channel formed in the bottom of the tube and extending towards said cathode from the point where the tube portions meet.

8. Alternating current mercury vapor apparatus comprising an arc tube having diverging branches at one end thereof adapted to carry anodes and having its other end adapted to hold the cathode mercury and a narrow depressed channel in the bottom of said tube between the cathode and the point of division between the diverging branches adapted to hold a thread of mercury connected to the cathode when the streams of anode mercury have flowed into their respec tive branch tubes by the tilting of the tube from the starting toward the operating position.

In testimony whereof we have signed our names to this specification.

' FREDERICK REYNOLDS.

ARTHUR LEONARD LEES. 

